Position

This site is in a Marine Protected Area (2004). A permit is required.
The site is entirely inside the Boulders Restricted Zone.

Name

"Maidstone Rock"is the name given the to the reef on the SA Navy charts. The deeper but more extensive reef to the east is known as Maidstone Reef, and the scattered outcrops around the two are generally referred to as the Maidstone Rocks.

Ammo Reef is the compact reef further to the east. Several large naval gun shells have been seen on the reef.

Depth

Maximum depth is about 21m on the sand at Maistone Rock, and the top of the highest pinnacle is about 7m at low tide.
Maximum depth at Maidstone Reef is about 25m on the sand, and the highest point is about 10m deep.
Ammo Reef is about 17m on top, and the surrounding sand is about 27m deep.

Topography

The reefs include a row of scattered granite pinnacles of various heights on a flat fine sand bottom, and a large contiguous section of reef of about 226m east to west by 113m north to south, rising about 15m from the sand at the highest point, but mostly somewhat lower. Across the sand bottom about 100m further east, a substantial outcrop known as Ammo reef rises from 27m on the sand to 17m on top, with several parallel cracks running roughly east-west.

Maidstone Rock is the highest of a dense cluster of very precipitous granite pinnacles on fairly flat sand bottom. The site is spectacular in good viz. The main cluster quite tightly packed, with the pinnacle ridges running more or less north east to south west. There are probably more pinnacles to the east, and to the north west but these have not yet been surveyed. A couple of the pinnacles have deep rounded undercuts part way up the sides, but not quite enough to trap air.

Maidstone Reef is a fairly flat topped area of bedrock that extends a few metres above the sand. Sand bottom at the edge of reef ranges from about 21 m to 24m near the rock, but to the north the sand slopes down visibly past a few outliers and reaches 26m quite nearby, at which stage it has flattened out. The central north side seems to have nore rugged topography, with a steep dropoff from above 18m to the sand. There is a large number of small boulders like scattered along the slopes to the south. The profile is steep and high along the north side, but flatter in most places. There is a large anchor lying on the reef just below 18m to the south.

Ammo Reef to th east of Maidstone reef is a fairly monolithic outcrop with marked groove along the length of top, and more parallel jointing to the north east. The top of reef about 17m deep, and the sand bottom at about 27m. The topography is not particularly rugged, and most of the reef slopes fairly gently down to the sand. A few fairly large bore naval shells have been seen on the reeftop. They appear to be about 125mm diameter, but are quite heavily encrusted.

Geology:
Late Pre-cambrian granite from the Peninsula pluton. Some of the pinnacles of the Maidstone Rock group have the characteristic rounded edges and corners of corestones, and the rounded undercuts in the tall pinnacles suggest that they were originally weathered underground. The Maidstone reef and Ammo reef outcrops have the typical rounded shape of corestones, and there is a large amount of relatively small boulder-rubble along the southern perimeter of Maidstone reef.

Conditions

The site is exposed to wind and waves from the south east, so should be dived in weaterly winds or a calm. The site is reasonably protected from south westerly swells, but long period swells from the south west will cause strong surge.

The site should usually be at it's best in winter but there may also be occasional opportunities at other times of the year.

Get in

Access to this site is by boat, It is about 4.4km from the Miller's Point slipway.

See

Marine life

Maidstone Rock

Typical of the outer reefs in this area, but not many sea fans. Different rocks have different characters with different dominant invertebrates. Mauve sea cucumbers, striped anemones, strawberry anemones, black brittle stars and common feather stars are abundant. Large numbers of large whelks with egg masses have been seen. Fish may include Roman and small shoals of Hottentot.

Reef scene at Maidstone Rock

Klipfish

The colonial ascidian "Blue Choirboys"

Small Abalone

Spider crab on Mauve sea cucumbers

Maidstone Reef

Large iron anchor, possibly from a RN ship of the early 19th century

Teat sponge with common feather stars

Echnoderms, sponges and hydroids on the reef

Ammo Reef

Features

There is a large iron Royal Navy style anchor about 6m long, 4m wide on top of Maidstone Reef just below the 18m contour to the south. The anchor has lost its stock and one fluke is broken, but still with the anchor. The crown is a slightly pointed curve, the flukes large and triangular, each about a metre long. The shank is about 6m long, lying roughly horizontal about half a metre above the reef. The ring is large, about 600mm diameter, suitable for use with thick natural fibre cable. There is no sign of a hole in the shank for an iron stock, so it may have had a wooden stock, as was common on older anchors of this type.

Photography

Macro or wide angle lenses are most suited to the site and the visibility to be expected.

Routes

No particular routes are known. Work your way along the line of pinnacle as suits you best.

Stay safe

Hazards

No site specific hazards are known.

Skills

No special skills required. Ability to deploy a DSMB recommended.

Equipment

No special equipment required. A DSMB is recommended to inform the boat of where you will be surfacing.